Trisunius ligulatus, Assing, 2011

Assing, V., 2011, Trisunius gen. nov. from the southern East Palaearctic and the Oriental regions (Coleoptera: Staphylinidae: Paederinae: Medonina), Linzer biologische Beiträge 43 (1), pp. 195-220 : 200-202

Trisunius ligulatus nov.sp. ( Figs 10-16 )

T y p e m a t e r i a l: Holotype Ƌ: " China (Yunnan) Baoshan Pref., Gaoligong Shan nr. Xiaoheishan N. R., 35 km SE Tengchong, 2110 m, 24°50'16''N, 98°45'43''E (prim. decid. forest, litter, sifted) 30. V.& 4.VI.2007 D.W. Wrase [11] / Holotypus Ƌ Trisunius ligulatus sp. n. det. V. Assing 2011" (cAss). Paratypes: 13 exs.: same data as holotype (cSch, cAss); 1 ex.: " China: Yunnan [CH07-11], Baoshan Pref., Gaoligong Shan, nr. Xiaoheishan N. R., 35 km SE Tengchong, 2110 m, 24°50'16''N, 98°45'43''E, decid. forest, litter, sifted, 30.V.2007, M. Schülke " (cSch); 2 exs.: " China: Yunnan [CH07-11A], Baoshan Pref., Gaoligong Shan, nr. Xiaoheishan N. R., 35 km SE Tengchong, 2110 m, 24°50'16''N, 98°45'43''E, decid. forest, fungi, sifted, 4.VI.2007, leg. A. Pütz " (cPüt); 3 exs.: " China: Yunnan, Baoshan Pref., Gaoligong Shan , W Pass 35 km SE Tengchong, 2100 m, 24°50'18''N, 98°45'43''E, devast. prim. dec. forest, litter, wood, mushrooms sifted, 25.VIII.2009, leg. M. Schülke [CH09-06]" (cSch, cAss); 5 exs.: " China (Yunnan) Baoshan Pref., mount. range 14 km E Tengchong, 1850 m, 25°00'28''N, 98°38'07''E, 1850 m [sic] (second. mixed forest, field edge, litter, debris sifted) 1.VI.2007 D.W. Wrase [16]" (cSch, cAss); 1♀: " China: Yunnan [CH07-17], Baoshan Pref., mountain range 25 km S Tengchong, 1900 m, 24°48'28''N, 98°32°03''E, dev. primery [sic] decid. forest, litter, fungi, sifted, 2.VI.2007, M. Schülke " (cSch); 2 exs.: " China: Yunnan, Baoshan Pref., mount. range 25 km S Tengchong, 1900 m, 24°48'21''N, 98°32°05''E, cleft with devast. primary forest, litter & mushr. sifted, 30.VIII.2009, leg. M. Schülke [CH09-18]" (cAss, cSch); 2 exs.: " China (Yunnan) Dehong Dai Aut. Pref., mount. range 31 km E Luxi, 2280 m, 24°29'31''N, 98°52'58''E (grassland, pasture, under stones & shrubs, in moss & litter) 3.VI.2007 D.W. Wrase [19]" (cSch, cAss); 1 ex.: " China: Yunnan [CH07-19], Dehong Dai Aut. Pref., mountain range 31 km E Luxi, 2280 m, 24°29'31''N, 98°52'58''E, secnd. pine forest with old decid. trees, litter sifted 3.VI.2007, M. Schülke " (cSch); 2 exs.: " China: Yunnan [CH07-30], Nujiang Lisu Aut. Pref., Nu Shan , 7 km NNW Coajian, 25°43'29''N, 99°07'57''E, 2420 m, second. pine forest with shrubs, litter, bark sifted, 11.VI.2007, M. Schülke " (cSch); 3 exs.: same data, but "leg. A. Pütz " (cPüt, cAss); 1 ex.: " China (Yunnan) Nujiang Lisu Aut. Pref., Nu Shan , 7 km NNW Coajian, 2420 m, 25°43'29''N, 99°07'57''E (second. pine forest with shrubs, litter, moss sifted) 11.VI.2007 D.W. Wrase [30]" (cAss); 1 ex.: " China: Yunnan [CH07-20], Nujiang Lisu Aut. Pref., creek valley 3 km SE Gongshan, 1450-1500 m, 27°43'02''N, 98°41'27''E, litter, moss, sifted, 5.VI.2007, leg. A. Pütz " (cAss) .

D e s c r i p t i o n: Body length 3.0- 3.7 mm. Habitus as in Fig. 10 . Coloration: head dark-reddish to blackish-brown; pronotum and elytra reddish to dark-brown; abdomen reddish-brown to dark-brown, with the apex (segments VIII-X) reddish; legs and antennae reddish.

Head ( Figs 11-12 ) weakly oblong, approximately 1.05 times as long as wide; punctation fine and moderately dense; interstices with fine, but distinct microsculpture. Eyes approximately half as long as postocular region in dorsal view, or nearly so. Anterior margin of labrum with two distinct teeth on either side of median incision.

Pronotum ( Figs 11-12 ) approximately 1.1 times as long as wide and 0.90-0.95 times as wide as head; punctation rather fine and dense, more distinct than that of head; midline with narrow impunctate band; interstices without microsculpture.

Elytra with weakly pronounced dimorphism, in submacropterous morph ( Fig. 12 ) 0.8-0.9 times as long as pronotum, in macropterous morph ( Fig. 11 ) 0.95-1.00 times as long as pronotum; humeral angles marked; punctation dense and shallow, less defined than that of pronotum; interstices without microsculpture. Hind wings either fully developed (macropterous morph) or of reduced length and approximately twice as long as elytra (submacropterous morph). Metatarsomere I approximately as long as II.

Abdomen slightly broader than elytra, widest at segment VI; punctation fine and dense; interstices with distinct microsculpture; posterior margin of tergite VII with palisade fringe.

Ƌ: sternite VII with impression in posterior median portion, on either side of this impression with extensive cluster of long dark setae ( Fig. 13 ); sternite VIII with median impression and with deep and rather narrow V-shaped excision ( Fig. 14 ); aedeagus approximately 0.45 mm long; ventral process somewhat sinuate in lateral view and apically spoon-shaped in ventral view ( Figs 15-16 ).

E t y m o l o g y: The specific epithet is an adjective derived from the Latin noun ligula (small spoon) and refers to the shape of the apex of the ventral process of the aedeagus in ventral view.

C o m p a r a t i v e n o t e s: As can be inferred from the similarly derived shape and chaetotaxy of the male sternites VII and VIII, as well as from the morphology of the aedeagus (shape of ventral process; shape of dorso-apical structures), T. ligulatus is the adelphotaxon of the similar T. spathulatus . Both species are reliably separated only by the shape of the aedeagus (shape of ventral process both in ventral and in lateral view; shape of dorso-apical structures).

D i s t r i b u t i o n a n d n a t u r a l h i s t o r y: The species was collected in several localities in the Gaoligong Shan and the Nu Shan in western Yunnan. The distributions of T. ligulatus (extreme west of Yunnan) and T. spathulatus (southwestern Yunnan), its adelphotaxon, are apparently parapatric. The specimens were sifted from litter and debris in forests, on one occasion also in grassland, at altitudes of 1450-2420 m in May, June, and August. Syntopic species are T. cultellatus and T. truncatus .

Figures

Figs 10-16: Trisunius ligulatus nov.sp.: (10) habitus (macropterous morph); (11) forebody (macropterous morph); (12) forebody (submacropterous morph); (13) male sternite VII; (14) male sternite VIII; (15) aedeagus in lateral view; (16) ventral process of aedeagus in ventral view. Scale bars: 10: 1.0 mm; 11-12: 0.5 mm; 13-14: 0.2 mm; 15-16: 0.1 mm.